Rotary mechanical seal with telescoping parts



Nov. 23, 1954 P. T. HAAKE ROTARY MECHANICAL SEAL WITH TELESCOPING PARTSOriginal Filed Jan. 13, 1950 INVENTOR.

United States Patent Ofifice Re. 23,898 Reissued Nov. 23, 1954 ROTARYIVIECHANICAL SEAL WITH TELESCOPING PARTS Paul T. Haake, Park Ridge,111., assignor to Crane Packing Company, Chicago, Ill., a corporation ofIllinois Original No. 2,610,075, dated September 9, 1952, Serial No.138,506, January 13, 1950. Application for reissue December 23, 1953,Serial No. 400,157

3 Claims.

The present invention relates to rotary mechanical seals, and moreparticularly to a seal assembly for sealing relatively rotatable membersas for example a shaft and a housing member therefor.

It frequently occurs in the design of such [seat] seal assemblies thatthree or more parts must be telescoped one within the other with theintermediate part or parts compressed between the outer and inner parts.Where the telescoping parts are made by a molding process and ofmaterials which are deformable and resilient, it is difficult to controlthe diameters of the parts sufficiently closely to permit the parts tobe assembled in the desired telescoping relation. Thus, if one part is amolded sealing washer made of a thermosetting resin, one adjacenttelescoping part is a rubber sleeve similarly made in a mold, and thethird member is a metallic ring made in a punch press or the like, itmay frequently occur that the permissible deviation from the desireddiameters, i. e., the tolerances, may be cumulative in a direction tocause the space between the washer and the ring to be too small for therubber member. When this happens, one of the three members must bediscarded and replaced with another which will permit the three membersto be telescoped. This increases the assembly time and also increasesthe number of rejected pieces.

The object of this invention is to provide a design of three telescopingparts, the intermediate one of which is to be compressed between theother two which will permit the assembly of any three partsindependently of variations t diameters of the parts within normalmanufacturing imits.

This object will become apparent from the following description whentaken together with the accompanying drawings, in which Fig. 1 is aquarter-section taken through a rotary mechanical seal having threeparts assembledin accordance with the teachings of this invention; and

Fig. 2 is an exploded view of the three elements to be telescopedshowing the method of forming each part in accordance with thisinvention.

In the embodiment chosen for illustration, there is shown a shaft 10passing through an opening 11 in a housing 12 having a recess 13 formedtherein. On said shaft is pressed the hub 14 of vaned pump impeller orthe like, said press-fit being also fluid-tight. It is contemplated thatthe exterior surface 15 of the impeller hub 14 will be exposed to fluid.

In recess 13 is disposed a retainer 16 having a cylindrical wall 17which is pressed into recess 13 with a fluidtight fit. A flange 18 onwall 17 locates the retainer in recess 13.

Within retainer 16 is a tubular sealing element 19 made of resilientdeformable material such as rubber, either synthetic or natural, or acombination of the two, said element 19 having a substantiallycylindrical part 20, a shoulder 21, and a second cylindrical section 22.A sealing washer 23 made of a synthetic resin or other suitable moldedmaterial is telescoped into tubular element 19 and is provided with ashoulder 24 having an outer cylindrical surface 25. Said washer 23 isalso provided with a radially disposed sealing surface 26 which contactsa similarly radially disposed sealing surface 27 on hub 14 with a Vfluid-tight fit. .A spring 28 bears at one end against washer 23 and atthe other end against a flange 29 formed on tubular member 19, saidflange in turn abutting on a radially disposed wall 30 on retainer 16.

' A rigid band 31, preferably made of stamped metal, telescopes over thesecond cylindrical portion 22 of tubular member 19 and is intended tocompress the said second tubular portion 22against washer 23 so as toform a fluidtight fit between the tubular member and washer. A flange 32on rigid ring 31 abuts on shoulder 21 on tubular member 19 and serves tolocate the ring on the tubular member.

It is apparent thus far that the dimensions of the telescoping partsmust always be such that the second tubular portion 22 of the tubularmember 19 will be compressed against washer 23 in order to insure afluid-tight seal. The accuracy with which these parts are made, however,has a decided bearing on their cost, it being generally understood thatthe smaller the tolerance permitted on the parts, the more expensive theparts become. Custom and usage in the trade, however, have establishedcertain to]- erances as normal, and if the normal tolerances can beaccepted, the lowest prices will prevail. The normal tolerances,however, may result in an excessive amount of material in the secondcylindrical portion 22 which will resist the telescoping action and makeit necessary to discard a relatively large number of tubular sealingmembers 19 in addition to delaying the assembly of the unit and thusdecreasing the number of such units which may be made in a given time.

When the interfitting parts are made in accordance with this invention,the normal tolerances can be utilized without any loss of time andwithout rejects for excessive material to be compressed between the ring31 and washer 23. Referring to Fig. 2, it will be observed that washer23 is provided with a chamfer 33 on the outer surface thereof, so thatthe cylindrical portion 25 remaining is relatively small. The secondcylindrical portion 22 of tubular member 19 is provided with a chamfer34 which terminates at the juncture of a line a which is an extension ofthe radial surface 35 on tubular member 19 and the outer cylindricalsurface 36 of the second tubular region 22. Ring 31 is belied at 37 sothat its greatest internal diameter is greater than the outside diameterof cylindrical surface 36.

As shown in dotted lines b, when the washer is assembled with respect tothe tubular member 19, there is only a relatively narrow portion of thesecond tubular region 22 which must be compressed between ring 31 andwasher 23. One either side of this narrow portion, there is a spaceprovided for the excess material of the second cylindrical region 22 toflow into and thus relieve the compressed region of any excessivepressure which may be built up. One such space is provided by chamfer 33and the other space is provided by chamfer 34. Thus the actual amount ofcompressed material which must be flowed is relatively small and suchmaterial as must flow has a space into which it can go. It is apparent,therefore, that relatively wide variations in the diameter of the washeror the cylindrical region 22 of a resilient member 19, or of theinternal diameter of the ring 31 may be tolerated without any loss oftime on the part of the assembly operator, or loss of parts throughrejection for improper size.

It is obvious that the principle described above may be appliedgenerally to any series of objects which must be telescoped one in theother with an intermediate object compressed between its inner and outertelescoping objects. Thus, for example, the principle of this inventionmay be applied to closures for containers as well as to seals, which ina sense, are likewise closures of a specific variety. The scope of thisinvention, therefore, should not be limited to the foregoingillustrative embodiment but should be determined by the appended claims.

What is claimed is:

1. A seal assembly for relatively rotatable members including a shaftmember and a housing member surrounding the same, said assemblycomprising a ring-like sealing washer adapted to be telescopicallyreceived over said shaft member, said washer being formed of a rigid,noncompressible material, and having a forward radially disposed runningsealing surface adapted to frictionally bear against a radial surfacesubstantially normal to the shaft and movable with the latter, saidwasherigbeing formed with an annular recess providing a rearwardlyfacing radially disposed shoulder and a cylindrical sur face rearwardlyof said shoulder, the periphery of said washer immediately forwardly ofsaid shoulder being formed with a narrow cylindrical band-like regionand having a relief area forwardly of said band-like region of reduceddiameter, an elastomeric sealing sleeve having a body portion and anoffset cylindrical portion at the forward end thereof and providing anintermediate connecting wall having a forwardly facing radially disposedshoulder, means for sealing said body portion to said housing, saidsleeve being telescopically received over said sealing washer with theoutwardly offset portion surrounding the outer periphery of the washerand with said body portion surrounding said cylindrical surface and withsaid shoulders in abutting relationship, and a rigid clamping ringtelescopically received over said sleeve, said ring having an innercylindrical surface surrounding said outwardly offset portion of thesleeve and compressing the latter inwardly and against the band-like andrelief area of the washer, the thickness of said offset cylindricalportion of said sealing sleeve being greater than the distance betweensaid cylindrical band-like region of the washer and the innercylindrical surface of said clamping ring whereby upon assembly of theWasher, sleeve and ring, a portion of the material of said sleeve iscaused to flow into said relief area.

2. A seal assembly for relatively rotatable members including a shaftmember and a housing member surrounding the same, said assemblycomprising a ring-like sealing washer adapted to be telescopicallyreceived over said shaft member, said washer being formed of a rigid,non compressible material, and having a forward radially disposedrunning sealing surface adapted to frictionally bear against a radialsurface substantially normal to the shaft 1 and movable with the latter,said washer being formed with an annular recess providing a rearwardlyfacing radially disposed shoulder and a cylindrical surface rearwardlyof said shoulder, the periphery of said Washer immediately forwardly ofsaid shoulder being formed with a narrow cylindrical band-like regionand having a relief area forwardly of said band-like region of reduceddiameter, an elastomeric sealing sleeve having a body portion and anoffset tubular portion at the forward end thereof and providing anintermediate connecting wall having a forwardly facing radially disposedshoulder, said offset tubular portion presenting an outer cylindricalsurface in the forward region thereof and a rearwardly and inwardlyinclined conical surface in the rear regions thereof, means for sealingsaid body portion to said housing, said sleeve being telescopicallyreceived over said sealing washer with the outwardly offset portionsurrounding the outer periphery of the Washer and with said body portionsurrounding said cylindrical surface and with said shoulders in abuttingrelationship, and a rigid clamping ring telescopically received oversaid sleeve, said ring having an inner cylindrical surface surroundingsaid outwardly offset portion of the sleeve and compressing the latterinwardly and against the band-like and relief area of the washer, theextreme forward rim of said clamping ring being flared radiallyoutwardly to facilitate assembly of the washer, sleeve and clampingring, the thickness of said offset cylindrical portion of said sealingsleeve being greater than the distance between said cylindrical bandlikeregion of the washer and the inner cylindrical surface of said clampingring whereby upon assembly of the washer, sleeve and ring,'a portion ofthe material of said sleeve is caused to flow into said relief area.

3. A seal assembly for relatively rotatable members including a shaftmember and a housing member surrounding the some, said assemblycomprising a ring-like sealing washer adapted to be telescopicallyreceived over said shaft member, said washer being formed of a rigid,noncompressible material, and having a forward radially disposed runningsealing surface adapted to frictionully bear against a radial surfacesubstantially normal to the shaft and movable with the latter, saidwasher being formed with a rearwardly facing surface, the periphery ofsaid washer beginning at said rearwardly facing surface and extendingforwardly therefrom a short distance being cylindrical and providing aband-like area, the periphery of the washer beginning at a terminationof said bandlike area and extending forwardly therefrom providing arelief area the surface of which at all parts therealong isdimensionally of less diameter than the diameter of said cylindricalband-like area, an elastomeric sealing sleeve having a body portion andan ofiset cylindrical portion at the forward end thereof and providingan intermediate connecting wall having a forwardly facing radiallydisposed shoulder, means for sealing said body portion to said housing,said sleeve being telescopically received over said sealing washer withthe outwardly ofiset portion surrounding said cylindrical band-likeregion and said relief area and with said shoulder abutting saidrearwarcfly facing surface, and a rigid clamping ring telescopicallyreceived over said sleeve, said ring having an inner cylindrical surfacesurrounding said outwardly offset portion of the sleeve and compressingthe latter inwardly and tightly against the band-like region and causingthe same to flow into the relief area of the washer, the forward rim ofsaid clamping ring remaining wholly outside said inner cylindricalsurface of the ring.

References Cited in the file of this patent or the original patentUNITED STATES PATENTS Number Name Date 1,640,940 Jaeger Aug. 30, 19271,671,903 Iaeger May 29, 1928 1,807,187 White May 26, 1931 2,192,395 LaBour Mar 5, 1940 2,404,690 Caserta July 23, 1946 2,474,123 Schmitz June21, 1949 2,489,545 Storer et al Nov. 29, 1949 2,601,996 Sefren July 1,1952 2,610,871 Woodson Sept. 16, 1952 2,645,508 Payne July 14, 1953

